Abstract : In order to examine the synoptic-scale time variability (oscillation periods of 2 to 6 days) in the zonal and meridional wind components and in the temperature at altitudes 25 to 60 km, a computer program for wave period analysis was devised and applied to rocketsonde data of the Meteorological Rocket Network. The method consisted of fitting sinusoidal waveforms of various periods and phases to data in biweekly periods and evaluating the goodness of fit. Simple mathematical considerations and results from numerous tests with hypothetical data for idealized oscillations of known characteristics showed that the axis of symmetry and amplitude of the wave to be fitted to the data could be represented by the monthly mean and the square root of 2 times the standard deviation of the daily values, respectively. Aliasing effects would be minimized as long as ther were at least 12 observations during the month. (Modified author abstract)